Fixed #617. Proved the issue #617 and fixed it.

Adds now always the `Engine` vendor information in `MysqlSchemaParser` no matter if the build property `addVendorInfo` is true or not, because we need it in `MysqlPlatform` to check whether the table is `InnoDB` and thus with foreignKey support.
If `addVendorInfo` is true, it extracts **all** vendor information (as before).
Added a test that proves the bug and a helper class for more tests like that.
Split the `testForeignKey` into several methods. Added some phpdoc so its cleaer
bump 1.6.9-dev version
Merge branch '1.6'
Fixed typos
Merge pull request #628 from  pborreli/typos
Fixed some typos
Don't null size field when scale specified

This is an issue that I come upon using propel migration. It always tried to migrate my decimal column with the same values.

After inspecting closely I have figured that reverse schema parser sets null to $size variable (even if $scale) is specified.

This way, when migrator compares columns it has $size = 10 in schema.xml and $size = null in database (because reverse mysql class changes native sizes to null).

Real life example:
XML:
latitude: { phpName: Latitude, type: DECIMAL, size: 10, scale: 7, required: false }

DB:
  `latitude` decimal(10,7) DEFAULT NULL,


produces migration queries as such:

getUpSQL:
ALTER TABLE `venues` CHANGE `latitude` `latitude` DECIMAL(10,7);

getDownSQL:
ALTER TABLE `venues` CHANGE `latitude` `latitude` DECIMAL;


even though database is already set propely with size and scale.
Update generator/lib/reverse/mysql/MysqlSchemaParser.php

fix typo
add tests for issue #621
Merge pull request #621 from fliespl/patch-1
Don't null size field when scale specified
[Sluggable] add test to prove issue with slug ending with 0XYZ
{Sluggable] fix issue with slug ending with 0XYZ
Merge pull request #632 from jaugustin/fix-sluggable-exception

Sluggable fix an exception with slug endding with 0XXX
Support for quoting aliases
Remove not valid anymore comment
Remove unnecessary .''
Make `testQuotingIdentifiers()` abstract and allow each `DB<Adapter>Test` to implement it
Merge pull request #635 from arvenil/always-quote-aliases

Always quote aliases
Bugfix for join equality when default join type is used

$j1 = new Join('foo', 'bar');
$j2 = new Join('foo', 'bar', 'INNER JOIN');
$this->assertTrue($j1->equals($j2));
Merge pull request #638 from arvenil/fix-join-equality

Bugfix for join equality when default join type is used